From 6bc6d433aaed4d4a5d5be44e70d9de865a850048 Mon Sep 17 00:00:00 2001
From: Martin Sperl <kernel@martin.sperl.org>
Date: Tue, 26 Apr 2016 14:59:21 +0000
Subject: [PATCH] MISC: bcm2835: smi: use clock manager and fix reload issues

Use clock manager instead of self-made clockmanager.

Also fix some error paths that showd up during development
(especially missing release of dma resources on rmmod)

Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
---
 drivers/misc/bcm2835_smi.c | 86 +++++++++++++++-------------------------------
 1 file changed, 28 insertions(+), 58 deletions(-)

--- a/drivers/misc/bcm2835_smi.c
+++ b/drivers/misc/bcm2835_smi.c
@@ -34,6 +34,7 @@
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include <linux/clk.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
@@ -62,7 +63,7 @@
 struct bcm2835_smi_instance {
 	struct device *dev;
 	struct smi_settings settings;
-	__iomem void *smi_regs_ptr, *cm_smi_regs_ptr;
+	__iomem void *smi_regs_ptr;
 	dma_addr_t smi_regs_busaddr;
 
 	struct dma_chan *dma_chan;
@@ -72,8 +73,7 @@ struct bcm2835_smi_instance {
 
 	struct scatterlist buffer_sgl;
 
-	int clock_source;
-	int clock_divisor;
+	struct clk *clk;
 
 	/* Sometimes we are called into in an atomic context (e.g. by
 	   JFFS2 + MTD) so we can't use a mutex */
@@ -82,42 +82,6 @@ struct bcm2835_smi_instance {
 
 /****************************************************************************
 *
-*   SMI clock manager setup
-*
-***************************************************************************/
-
-static inline void write_smi_cm_reg(struct bcm2835_smi_instance *inst,
-	u32 val, unsigned reg)
-{
-	writel(CM_PWD | val, inst->cm_smi_regs_ptr + reg);
-}
-
-static inline u32 read_smi_cm_reg(struct bcm2835_smi_instance *inst,
-	unsigned reg)
-{
-	return readl(inst->cm_smi_regs_ptr + reg);
-}
-
-static void smi_setup_clock(struct bcm2835_smi_instance *inst)
-{
-	dev_dbg(inst->dev, "Setting up clock...");
-	/* Disable SMI clock and wait for it to stop. */
-	write_smi_cm_reg(inst, 0, CM_SMI_CTL);
-	while (read_smi_cm_reg(inst, CM_SMI_CTL) & CM_SMI_CTL_BUSY)
-		;
-
-	write_smi_cm_reg(inst, (inst->clock_divisor << CM_SMI_DIV_DIVI_OFFS),
-	       CM_SMI_DIV);
-	write_smi_cm_reg(inst, (inst->clock_source << CM_SMI_CTL_SRC_OFFS),
-	       CM_SMI_CTL);
-
-	/* Enable the clock */
-	write_smi_cm_reg(inst, (inst->clock_source << CM_SMI_CTL_SRC_OFFS) |
-	       CM_SMI_CTL_ENAB, CM_SMI_CTL);
-}
-
-/****************************************************************************
-*
 *   SMI peripheral setup
 *
 ***************************************************************************/
@@ -894,42 +858,40 @@ static int bcm2835_smi_probe(struct plat
 	struct device_node *node = dev->of_node;
 	struct resource *ioresource;
 	struct bcm2835_smi_instance *inst;
+	const __be32 *addr;
 
+	/* We require device tree support */
+	if (!node)
+		return -EINVAL;
 	/* Allocate buffers and instance data */
-
 	inst = devm_kzalloc(dev, sizeof(struct bcm2835_smi_instance),
 		GFP_KERNEL);
-
 	if (!inst)
 		return -ENOMEM;
 
 	inst->dev = dev;
 	spin_lock_init(&inst->transaction_lock);
 
-	/* We require device tree support */
-	if (!node)
-		return -EINVAL;
-
 	ioresource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	inst->smi_regs_ptr = devm_ioremap_resource(dev, ioresource);
-	ioresource = platform_get_resource(pdev, IORESOURCE_MEM, 1);
-	inst->cm_smi_regs_ptr = devm_ioremap_resource(dev, ioresource);
-	inst->smi_regs_busaddr = be32_to_cpu(
-		*of_get_address(node, 0, NULL, NULL));
-	of_property_read_u32(node,
-			     "brcm,smi-clock-source",
-			     &inst->clock_source);
-	of_property_read_u32(node,
-			     "brcm,smi-clock-divisor",
-			     &inst->clock_divisor);
+	if (IS_ERR(inst->smi_regs_ptr)) {
+		err = PTR_ERR(inst->smi_regs_ptr);
+		goto err;
+	}
+	addr = of_get_address(node, 0, NULL, NULL);
+	inst->smi_regs_busaddr = be32_to_cpu(addr);
 
 	err = bcm2835_smi_dma_setup(inst);
 	if (err)
-		return err;
+		goto err;
 
-	/* Finally, do peripheral setup */
+	/* request clock */
+	inst->clk = devm_clk_get(dev, NULL);
+	if (!inst->clk)
+		goto err;
+	clk_prepare_enable(inst->clk);
 
-	smi_setup_clock(inst);
+	/* Finally, do peripheral setup */
 	smi_setup_regs(inst);
 
 	platform_set_drvdata(pdev, inst);
@@ -937,6 +899,9 @@ static int bcm2835_smi_probe(struct plat
 	dev_info(inst->dev, "initialised");
 
 	return 0;
+err:
+	kfree(inst);
+	return err;
 }
 
 /****************************************************************************
@@ -950,6 +915,11 @@ static int bcm2835_smi_remove(struct pla
 	struct bcm2835_smi_instance *inst = platform_get_drvdata(pdev);
 	struct device *dev = inst->dev;
 
+	dmaengine_terminate_all(inst->dma_chan);
+	dma_release_channel(inst->dma_chan);
+
+	clk_disable_unprepare(inst->clk);
+
 	dev_info(dev, "SMI device removed - OK");
 	return 0;
 }
